When is CD 1

Tara • 💍 married 💕ttc 👶🏼 number✌🏻after rainbow IUI babe. fur-mom to joey 🐶

Trying to figure out when to start clomid which will be day 3. My AF was slight spotting last night at like 10pm then full fires at 430am today. So is CD 1 Saturday night or Sunday morning?!